Welcome to NASIOC - The world's largest online community for Subaru enthusiasts!

Welcome to the NASIOC.com Subaru forum.

You are currently viewing our forum as a guest, which gives you limited access to view most discussions and access our other features. By joining our community, free of charge, you will have access to post topics, communicate privately with other members (PM), respond to polls, upload content and access many other special features. Registration is free, fast and simple, so please join our community today!

If you have any problems with the registration process or your account login, please contact us.

Anyhow, a pretty stupid question.... I've seen a lot of people wrap their headers w/fibreglass - i'm thinking that this is to keep exhaust gasses up, hence speeding up their flow backwards. Therfore, i'm thinking of maybe wrapping my exhaust to see if there is a diff. I'm currently running a 2.5" catback on an na engine - would wrapping the exhaust alleviate "some" of the backpressure problems due to the large diam. of the exhaust piping? Just a thought, please don't flame me. Also, if i did decide to wrap the exhaust, would there be problems w/ rust due to moisture and debris sandwiched up between the fibre and exhaust? Thanks.

I don't know about the WRX, but the 2.5RS is pretty much wrapped already down to the cats.

The metal "housing" around the exhaust appears to have insulation inside it between it and the exhaust pipe.

As far as whether or not wrapping the exhaust is helpful, I would say yes. Keeping the gasses at a higher temperature will keep velocity up. How much it helps is a question that only a dyno would answer. Nothing compares to real world testing.

The only reason the pipe would "rot" would be rusting through. That usually requires moisture. Exhaust tends to get kind of warm and generally evaporates most of the moisture on it. True the wrap will tend to hold the moisture more than without the wrap, but I have wrapped exhaust in the past without any excessive rust problems.

I have seen regular mild-steel headers rust through over the period of 6 month. These were mild steel and were brand new... not the stainless alloy a new car exhaust is made of. I don't know what it would do to any other material. Personally, I wouldn't go near the stuff based on experience. The benifits don't outweigh the potentional losses.

I have GSXR that had wrapped headers on it, they rusted like crazy. I could tell no discernable difference in the power output. I know I'm comparing apples to oranges, but to me it seems the hassle of wrapping them doesn't make up for the slight advantage that would be gained. Just my humble opinion